Edgar d



(No Model.)

E. D. JOHNSTON.

GRAIN TANK.

Patented Deo. 14,1897.

1r, vwww WSSQAttor-ney UNTTEn STATES PATENT OFFICE.

EDGAR D. JOHNSTON, OF CONNERSVILLE, INDIANA, ASSIGNOR TO THE STEEL STORAGE AND ELEVATOR CONSTRUCTION COMPANY, OF SAME PLACE.

GRAlN-TAN K.

SPECIFICATION forming part of Letters Patent No. 595,310, dated December 14, 1897.

Application led May 21,1897. Serial No. 637,507. (No model.)

To a/ZZ whom, z5 may concern.-

Be it known that I, EDGAR D. JOHNSTON, of Oonnersville, Fayette county, Indiana, have invented certain new and useful Improvements in Grain-Tanks, of which the following is a specification.

This invention pertains to improvements in vertically-disposed grain-tanks; and the improvements will be readily understood from the following description, taken in connection with the accompanying drawings, in which-- Figure l is a sectional plan of a grain-tank embodying myimprovement, and Fig. 2 a vertical diametrical section of the base of the tank.

In the drawings, l indicates the foundation, on which the tank rests; 2, the body of the tank, the same being a vertically-disposed cylinder` with its wall resting on the foundation and having a bottom in air-tight juncture with the base of the peripheral wall; 3, a diametrically-disposed hollow ridge above the bottom of the tank, its wall sloping angularly downward; il, angularly-disposed walls sloping upwardly from nearthe base of ridge 3 into conjunction with the peripheral wall of the tank, a pair of cutters thus being formed across the tank between ridge 3 and walls 4; 5, ridges extending transversely between ridge 3 and walls 4.; 6, passage-ways in the foundation below the bottom of the tank and under the bases of the cutters formed between ridge 3 and walls 4, these passage-ways being adapted to receive conveyers of any ordinary construction; 7, gated openings in the base of the tank at the base of the ridges and walls 4, these openings discharging into the passageways 6, so that the discharged grain may be received upon such conveying apparatus as may be disposed in the passage-ways; 8, the chambers formed within the ridges and below walls 4., these chambers being all in communication with each other and being air-tight, so far as the bottom and peripheral wall of the tanks are concerned; 9, a compressed-air inlet from the exterior of the tank into chambers S lO, a series of small air-ports in walls 4L and in the walls of the ridges, placing the interior of the tank in communication with chambers 8, and l1, hoods projecting over the air-ports l0 at a slight distance above the ports, these hoods having, preferably, the form of strips or rings secured against the ported walls, so

as to cover each a series of the ports, these hoods being omitted from many of the ports in order to more clearly exhibit the disposition of the ports.

It has been found in practice that the pressure at the foot of a column of grain does not increase at all with the height of the column 6o and that the result is that a high structure employed for the storage of grain may burst its walls but will never burst its bottom. If a tube be set upon end upon a plane surface and a quantity of grain be gently put into the tube, the grain will form a natural talus whose side angles will be the angle of repose of the grain. The weight of that talus is borne by the plane surface, and there is no side pressure or weight imposed upon the 7o tube, it being assumed that the talus has its base margin coinciding with the area of the tube. Now fill the tube with grain, and the result is that no greater weight is imposed upon the surface covered by the talus, but an outward pressure has been imposed upon the tube, and the friction due to this pressure supports the column of grain. The plane surface in question will of course have had imposed upon it an additional load, because So it is supporting the tube and the load supported by the tube. Assume, now, that the plane surface was formed of a piston-like section the size of the talus, so that this section could support the talus while the balance of the plane surface supported the tube.

In such case the maximum load would be imposed upon the interior section immediately when the talus was formed, and thereafter when the tube was filled the additional 9o load would be imposed upon the surrounding portion of the plane surface only.

In my improved construction of tank the foundation bears the weight of the main wall of the tank, and consequently supports the weight 0f a column of grain that may be in the tank minus the natural talus. The bottom struct-ure formed by the ridges and the walls 4 support the natural talus of grain and also that quantity of grain contained roo between the ridges and walls 4. The bottom structure thus supports a much greater quanv tity of grain than is represented by the natural talus, and all the grain in the tank may flow out readily through ports 7, under the control of valves 8, and be received and carried away by the conveyors.

If in emptying the tank there should be found a tendency for the grain to form an arch over the given discharge-opening and thus prevent the outflow, then such arch may be broken down by an outflow from a contiguous opening beyond the nearest ridge. In this Way the tank is rendered entirely sell'- emptying.

While the grain is in the tank compressed air enters chambers 8 frominlet 9 and, passing through ports 10, penetrates the body of grain in the base of the tank and rises through the column of grain, thereby Ventilating and drying it. The hoods prevent the passage of grain outwardly through the ports, even if the grains be small enough to pass through the ports, the grain arching at the free edge of the hood instead of finding its way under the hood. When the tank is to be emptied, then the gates at openings '7 are properly adjusted, the tank entirely emptying itself into the passage-ways 6 or into such conveying mechanism as may be arranged therein to carry the grain away, and during the final stage of the emptying process the inflow of air through ports 10 may be employed to aid the grain in its descent down the slopes of the ridges and walls 4, which slopes may therefore have a greater horizontal angle than corresponds with the angle of repose of grain.

I claim as my invention- 1. In a grain-tank, the combination, substantially as set forth, of a foundation, a vertically-disposed tank-wall resting thereon and having an air-tight bottom, a hollow ridge diametrically disposed over the bottom of the tank, Walls sloping angularly upward from near the base of said ridge into air-tight conjunction with the peripheral wall of the tank, hollow ridges disposed transversely between said first mentioned ridge and said wall,

gated openings at the bases of the ridges and angular walls, air-tight communicating chambers formed below the ridges and angular walls and communicating with the interior of the tank through ports in said angular walls and in the walls of the ridges, and a compressed-air inlet from the exterior of the tank to said chambers.

2. In a grain-tank, the combination, substantially as set forth, of a foundation, a vertically-disposed tank-wall resting thereon, intersecting ridges at the base of the tank having sloping walls converging to gated outletopenings, air-chambers below said sloping walls and communicating with the interior of the tank through ports in said sloping walls, hoods projecting outwardly over and above said ports, and a compressed-air inlet from the exterior of the tank to said chambers.

3. In a grain-tank, the combination, substantially as set forth, of a foundation, a vertically-disposed tank-wall resting thereon, intersecting ridges at the base of the tank having sloping walls converging to gated outletopenings, air-chambers below said sloping Walls and communicating with the interior of the tank through ports in said sloping walls, and a compressed-air inlet from the exterior of the tank to said chambers.

4. In a grain-tank, the combination, substantially as set forth, of a foundation, a vertically-disposed tank-wall resting thereon, intersecting ridges at the base of the tank having sloping walls converging to gated outletopenings, airchambers below said sloping walls and communicating with the interior of the tank through ports in said sloping walls, strips secured to the upper surfaces of said sloping Walls over and above said ports and each comprehendin g a series of said ports, and a compressed-air inlet from the exterior of the tank to said chambers.

EDGAR D. JOHNSTON.

Vitnesses:

R. H. GAMBLE, L. E. BLINN. 

